Effect of Massive Doses of Riboflavin, and Other Vitamins of the B Group, on Skin Carcinogenesis in Mice

IT came to our notice that a large group of Strong A mice in another institute fed on a diet known as " P.R.M. " unexpectedly failed to develop skin tumours in response to twice weekly applications of 0*1 ml. 0.1 per cent 3,4-benzopyrene for over one year.Because P.R.M. diet has a high content of vitamins of the B group, and because there are certain theoretical reasons for believing that ribo- flavin, in particular, might influence carcinogenesis, the experiments described below were undertaken.Previously Boutwell, Brush and Rusch (1949) investigated the effect of different levels of dietary vitamins of the B group on skin carcinogenesis by 3,4-benzopyrene.They reported a somewhat lower incidence of tumours in a group given a diet low in all B vitamins, but saw no difference in groups receiving diets rich in all, or individual, B vitamins.However, in their experiments the